Python: CLI Menu library

I started writing a small CLI menu library in python. I’m uncertain of the structure and scalability of the current code. For example the Menu.choice method would grow very large if were to add more options for navigation input. Could this be better done with a class to handle the input?

import sys import os   class Menu(object):     def __init__(self, *items, **kwargs):         self.items = []         self.title = kwargs.get('title', '')         self.header = kwargs.get('header', '')         for item in items:             self.add(item)      def add(self, *items):         for item in items:             self.items.append(item)             if hasattr(item, 'subMenu'):                 self.addParentToChild(item.subMenu)      def show(self):         clear()         if len(self.header):             self.showHeader()         if len(self.title):             self.showTitle()         for i, item in enumerate(self.items):             print('[{}] {}'.format(i + 1, item.title))         self.choice()      def choice(self):         while 1:             try:                 choice = input('> ')                 if choice is 'q':                     clear()                     sys.exit()                 if choice is 'b':                     if hasattr(self, 'parent'):                         self.parent.show()                     else:                         self.show()                         continue                 if not choice.isdigit():                     raise ValueError                 item = self.items[int(choice) - 1]                 if hasattr(item, 'callback'):                     item.callback()                 if hasattr(item, 'subMenu'):                     item.subMenu.show()                 if not hasattr(item, 'subMenu') and not hasattr(item, 'callback'):                     print('{} is an empty menu...'.format(item.title))             except (ValueError, IndexError) as e:                 self.show()                 continue      def addParentToChild(self, child):         child.parent = self      def showTitle(self):         print(self.title)      def showHeader(self):         print(self.header)   class MenuItem(object):     def __init__(self, title, subMenu=None, callback=None, tag=''):         self.title = title         if subMenu is not None:             self.subMenu = subMenu             if len(self.title):                 subMenu.title = self.title         if callback is not None:             self.callback = callback         if tag:             self.tag = tag   def clear():     if os.name == 'nt':         os.system('cls')     else:         os.system('clear') 

Do you have any advice or suggestions about the current structure or anything else that may cause issues later on?